UNIVERSITI MALAYA UNIVERSITY OF MALAYA PEPERIKSAAN IJAZAH SARJANA MUDA SAINS EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE SESI AKADEMIK 2009/2010 : SEMESTER 1 ACADEMIC SESSION 2009/2010 : SEMESTER 1 SCES2434 : KIMIA POLIMER 1 POLYMER CHEMISTRY 1 November 2009 November 2009 MASA : 2 jam TIME : 2 hours ARAHAN KEPADA CALON : INSTRUCTIONS TO CANDIDATES : Kertas soalan ini mengandungi dua bahagian, Bahagian A dan Bahagian B. This paper contains two sections, Section A and Section B. Jawab kedua-dua bahagian mengikut arahan yang diberi di bawah setiap bahagian. Answer both sections according to the instructions given in each section. (Kertas soalan ini mengandungi 5 soalan dalam 5 halaman yang dicetak) (This question paper consists of 5 questions on 5 printed pages)
SCES2434/02 BAHAGIAN A (50 MARKAH) SECTION A (50 MARKS) Jawab SEMUA soalan. Answer ALL questions. 1. (a) Struktur dan berikut mewakili dua monomer komersial. Bagi setiapnya, berikan nama polimer yang boleh dihasilkan dan struktur unit ulangan. Bagi setiap polimer, sebutkan kegunaan utama. Structures and represent two commercial monomers. For each one, give the name of the polymer it can produce, and the structure of the repeating unit. For each of polymer, state its main applications. CF 2 CF 2 NH 2 (CH 2 ) 9 COOH (10 markah/ marks) Tulis nota pendek tentang dua (2) topik daripada yang berikut. Write short note on two (2) of the following topics. Pengkelasan polimer mengikut mekanisma Classification of polymers by mechanisms Perbezaan utama antara proses pempolimeran manik dan pempolimeran larutan Major differences between the processes of bead polymerization and solution polymerization Kegunaan persamaan Carothers The application of Carothers Equation (c) Suatu sampel asid 6-hidroksilheksanoik telah dipanaskan dalam suatu reaktor pada suhu 220 C selama enam jam. Suatu polimer dengan jisim molekul purata 500,000 terbentuk. Tuliskan persamaan untuk menunjukkan tindak balas yang terlibat. Kirakan tahap tindak balas. Apakah masalah yang boleh timbul pada tahap tindak balas 100%? A sample of 6-hydroxyhexanoic acid was heated in a reactor at 220 C for six hours. A polymer with an average molecular weight of 500,000 was produced. Write the equation of the reaction. Calculate the reaction conversion. What would be the problem when reaction conversion reach 100%? (7 markah/ marks)
SCES2434/03 2. (a) Poli(vinil klorida) dan resin epoksi merupakan dua polimer yang digunakan secara meluas dalam industri. Satu adalah jenis termoplastik dan satu lagi jenis termoset. Senaraikan empat perbezaan utama antara dua polimer itu. Poly(vinyl chloride) and epoxy resin are two polymers that are widely used in industry. One is a thermoplastic while the other a thermoset. List four major differences between these two polymers. Tulis nota pendek tentang dua (2) topik daripada yang berikut. Write short note on two (2) of the following topics. Skima Q-e Alfred dan Price Q-e scheme of Alfred and Price Pempolimeran anion Anionic polymerization Biopolimer Biopolymer Bincangkan secara ringkas struktur kopolimer yang boleh didapati dalam pengkopolimeran dua monomer, A dan B. Discuss briefly the various possible structures in the copolymerization of two monomers, A and B. Nibah kereaktifan antara monomer A dan B adalah r 1 dan r 2. Apakah nilai r 1 dan r 2 supaya kita boleh dapat kopolimer berstruktur rawak? The reactivity ratios of monomers A and B are r 1 and r 2. What should be the values of r 1 and r 2 in order we can obtain a copolymer with random structure? (9 markah/ marks)
SCES2434/04 BAHAGIAN B (50 MARKAH) SECTION B (50 MARKS) Jawab SEMUA soalan. Answer ALL questions. 3. Polimetil metakrilat, PMMA, disediakan daripada metil metakrilat, MMA, melalui pempolimeran penambahan radikal bebas. Pempolimeran ini melibatkan beberapa langkah dan memerlukan satu pemula. Polymethyl methacrylate, PMMA, is prepared from methyl methacrylate, MMA by free radical addition polymerization. This polymerization involves few steps and requires an initiator. (a) Lukiskan struktur kimia bagi MMA dan PMMA. Draw the chemical structures of MMA and PMMA. Namakan satu pemula yang sesuai dan berikan struktur kimianya. Name one suitable initiator and give the chemical structure. (c) Terbitkan kadar pempolimeran dan nyatakan andaian-andaian yang dibuat. Derive the rate of polymerization and state the assumptions made. (d) Dengan menganggapkan tiada tindak balas pemindahan rantai, bincangkan bagaimana mengubah kepekatan monomer dan pemula mempengaruhi Assuming absence of chain transfer reactions, discuss how changing the concentrations of monomer and initiator affect the kadar pempolimeran rate of polymerization. darjah pempolimeran purata-nombor. number average degree of polymerization. (e) Jelaskan kesan tindak balas pemindahan rantai terhadap jisim molar purata dan mikrostruktur bagi polimer yang terhasil. Describe the effect of chain transfer reactions on the average molar mass and microstructure of polymer produced. (20 markah/ marks)
SCES2434/05 4. Satu sampel polisebar polistirena (PS) disediakan dengan mencampurkan tiga sampel monosebar dalam perkadaran berikut: 4 g PS dengan berat molekul 20,000, 3 gps dengan berat molekul 100,000 dan 3 g PS dengan berat molekul 1,000,000. A polydisperse sample of polystyrene (PS) is prepared by mixing three monodisperse samples in the following proportions: 4 g of PS with 20,000 molecular weight, 3 g of PS with 100,000 molecular weight and 3 g of PS with 1,000,000 molecular weight. Kirakan Calculate (iv) berat molekul purata-bilangan the number-average molecular weight berat molekul purata-berat the weight-average molecular weight berat molekul purata-z the z-average molecular weight indeks polisebaran the polydispersity index (10 markah/ marks) 5. (a) Jelaskan bagaimana suhu peralihan kaca dipengaruhi oleh sifat molekul bagi suatu polimer. Berikan contoh-contoh. Describe how glass transition temperature is affected by the molecular features of the polymer. Give examples. Jisim molar suatu polimer boleh diukur dengan menggunakan teknik osmometri membran. Bincangkan prinsip tekinik ini. Berikan kebaikan dan keburukan teknik ini. The molar mass of a polymer can be measured using the membrane osmometry technique. Discuss the principle of this technique. Include its advantages and disadvantages. (20 markah/ marks) TAMAT END